Problems of producing motor fuels from alternative raw materials

The mechanism and kinetics of reactions occurring in different processes of natural gas processing to motor fuels are considered. Among them are the syntheses of methanol, dimethyl ether, and gasoline from synthesis gas (syngas) and production of pure hydrogen from methanol. The general scheme of carbon-containing raw materials processing to produce motor fuels is considered using natural gas as example. The advantages of the direct synthesis of dimethyl ether (DME) from syngas (instead of methanol synthesis) over all processes producing motor fuels were shown. The synthesis of DME uses the syngas of almost any composition and, hence, the process scheme of carbon-containing feedstock syngas DME gasoline becomes universal and appropriate for processing various raw materials. Prospects of using methanol as an easily transportable source of pure hydrogen were considered. The steam reforming of methanol is a reaction inverse to its synthesis. The oxidation of residual CO in order to purify hydrogen is favored in the mode of catalyst surface ignition. Modern catalysts and methods for removal of CO traces can provide production of pure hydrogen by methanol processing with an efficiency appropriate, in principle, for using the corresponding devices aboard a vehicle.The materials of the report at the III International School Engineering Chemical Science for Advanced Technologies¹ and recent publication² were used in part.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2352–2363, November, 2004.     

APUSM technology for the production of BTX and LPG from pyrolysis gasoline using metal promoted zeolite catalyst

SK Corporation developed an advanced pyrolysis gasoline (pygas) upgrading (APU^SM) technology based on a catalytic process for producing valuable benzene, toluene and xylenes (BTX) and liquefied petroleum gas (LPG) from pygas containing aromatics and non-aromatic hydrocarbons. Hydrodealkylation of heavy aromatics and hydrocracking of non-aromatic hydrocarbons occurred with facility in the conversion of pygas over a proprietary catalyst, metal promoted zeolite. This catalytic process produced benzene and toluene with high purity corresponding to chemical grade while giving mixed xylenes with reduced ethylbenzene. In the present study, we described novel features of the APU^SM technology in terms of the process and catalyst. The influence of the process conditions was also examined. This technology has been commercially proven, and hence is available for licensing through Axens, which is a major engineering and licensing company.     

Benzene elimination from reformate gasoline by high pressure hydrogenation in a fixed-bed reactor

The reduction of benzene from benzene-rich real gasoline fractions has been studied in a high-pressure fixed-bed reactor using a Pt/TiO₂ catalyst. It was found that the yield of this process decreases with the toluene content in the feedstock, but it is independent of the kind of the saturated hydrocarbons. This revised version was published online in August 2006 with corrections to the Cover Date.     

Calculation of the formation energies of isolated vacancy and adatom-vacancy pair at low-index surfaces of fcc metals with MAEAM

The formation energies of isolated vacancy and adatom-vacancy pair (where the two are separated by a large distance) at low-index surfaces of fcc metals calculated by using the modifies analytical embedded atom method (MAEAM). The results predict the prevailing formation of vacancies on the surfaces (1 1 1), (1 0 0) (but Pd), Cu and Ni on the (1 1 0) surfaces at low temperature, and the defect formation energies consistently create in the sequence (1 1 0) → (1 0 0) → (1 1 1). With good accuracy, the calculated energy values coincide with those obtained by the embedded atom methods (EAM) and from experiments. The correctness of the method by which calculated the formation energies of point defects on the surface was proved.     

Experimental and modelling study of gasoline surrogate mixtures oxidation in jet stirred reactor and shock tube

The oxidation of several mixtures of surrogate for gasoline was studied using a jet stirred reactor and a shock tube. One representative of each classes constituting gasoline was selected: iso-octane, toluene, 1-hexene and ethyl tert-butyl ether (ETBE). The experiments were carried out in the 800-1880 K temperature range, for two different initial pressures (0.2 and 1 MPa), with an initial fuel molar fraction of 0.001. The equivalence ratio varied from 0.5 to 1.5. Each hydrocarbon sub-mechanism was validated using shock tube data. The full mechanism describing the surrogate fuel oxidation is constituted of the sub-mechanisms for each fuel components and by adding interaction reactions between different hydrocarbon fragments. Good agreement between the experimental results and the computations was observed under JSR and shock tube conditions.     

Measurement of mercaptans in gasoline

In an r-FIA single-line manifold, 10-l portions of 5,5-dithiobis (2-nitrobenzoic acid) and 2% (v/v) ethylenediamine in 80 20 inethanol: acetone are injected from pressurized containers via high-speed on/off valves into a flowing gasoline stream. The reaction product, 2-nitro-5-mercaptobenzoate, is detected optically at 412 nm after a reaction time of 15s. The system is intended for the measurement of mercaptans in the 0–2 mM (0–64 ppm S) concentration range. The response for C1–C10n-mercaptans ranges from 0.766–0.159 mAU/mM, the response to C1–C5n-mercaptans is 630 mAU/mM (±18.5% RSD). The response ratio of C1 and C5 mercaptans is 1 0.653. The system permits extreme conservation of reagents; only 10 l of each reagent is consumed per determination.     

FCC汽油模型化合物光催化氧化脱硫的研究

以噻吩的二甲苯溶液作为FCC汽油的模型化合物, 双氧水为氧化剂, 研究了在光催化作用下, 双氧水体积分数、 高速均质时间和二氧化钛的加入量等工艺条件对脱硫率的影响, 在适宜条件下, 模型化合物的脱硫率可达到80%以上. 以FCC汽油为实际体系, 在适宜的光催化条件下, 脱硫率可达到59%. 分析结果表明, 含硫化合物的氧化产物为更高极性的物质.     

汽油样品类型的模式识别研究与应用

研究了应用化学计量学方法解决汽油单体烃的气相色谱分析中单体烃定性库的自动选择问题。通过提取汽油单体烃谱图中的29个组分及其含量信息作为特征值,利用主成分分析法对不同工艺得到的催化裂化汽油、焦化汽油、直馏汽油、重整汽油和烷基化汽油进行分类,结合相似分析方法(即SIMCA方法)建立了各类汽油样本的类模型,借助这些类模型可以实现对未知样本的类型判别。所提出的识别方法可方便快速地判别待分析样品所属的汽油类别,并据此推荐适合该样品的定性模型库,从而实现汽油单体烃的快速、自动分析。     

Numerical and experimental study on effect of wall geometry on wall impingement process of hollow-cone fuel spray under various ambient conditions

The spray–wall impingement process in gasoline direct injection (GDI) engines, which is caused by the interaction among spray, wall and air to move the air–fuel mixture near the spark plug, directly influences the engine performance and emissions. Therefore, a detailed understanding of this process is very important in designing an injection system and controlling a strategy of GDI engines. The purpose of this study is to understand the spray–wall impingement characteristics for more efficient designing of the injection system in GDI engines and to supply the fundamental data under engine operation conditions. The wall impingement processes of hollow-cone fuel spray according to ambient gas conditions and wall geometry are calculated by validated spray models. The calculated results were compared with the experimental results obtained by the laser-induced exciplex fluorescence (LIEF) technique. It was found that the spray and vortex cloud at the high ambient pressure were distributed at inner area of cavity and the more fuel film mass observed at this condition. The fuel film mass decreased with the increase of ambient temperature, while the fuel film mass increased at high cavity angles.     

Multi-location laser ignition using a spatial light modulator towards improving automotive gasoline engine performance

We report on a study into multi-location laser ignition (LI) with a Spatial Light Modulator (SLM), to improve the performance of a single cylinder automotive gasoline engine. Three questions are addressed: i/ How to deliver a multi-beam diffracted pattern into an engine cylinder, through a small opening, while avoiding clipping? ii/ How much incident energy can a SLM handle (optical damage threshold) and how many simultaneous beam foci could thus be created? ; iii/ Would the multi-location sparks created be sufficiently intense and stable to ignite an engine and, if so, what would be their effect on engine performance compared to single-location LI? Answers to these questions were determined as follows. Multi-beam diffracted patterns were created by applying computer generated holograms (CGHs) to the SLM. An optical system for the SLM was developed via modelling in ZEMAX, to cleanly deliver the multi-beam patterns into the combustion chamber without clipping. Optical damage experiments were carried out on Liquid Crystal on Silicon (LCoS) samples provided by the SLM manufacturer and the maximum safe pulse energy to avoid SLM damage found to be 60 mJ. Working within this limit, analysis of the multi-location laser induced sparks showed that diffracting into three identical beams gave slightly insufficient energy to guarantee 100% sparking, so subsequent engine experiments used 2 equal energy beams laterally spaced by 4 mm. The results showed that dual-location LI gave more stable combustion and higher engine power output than single-location LI, for increasingly lean air-fuel mixtures. The paper concludes by a discussion of how these results may be exploited.